Slub catcher



Nov. 8, 1960 s. L. ABBOTT 2,

SLUB CATCHER Filed Dec. 15, 1958 3 Sheets-Sheet 1 Nov. 8, 1960 s. L. ABBOTT 2,958,922

' SLUB CATCHER Filed Dec. 15, 1958 3 Sheets-Sheet 2 "a little beyond the place where the United States PatentO SLUB CATCHER Samuel L. Abbott, Wilton, N.H., assignor to Abbott Machine Co., Inc., Wilton, N.H., a corporation of New Hampshire Filed Dec. 15, 1958, set. No. 780,457

5 Claims. or. 28-64) invention relates to slub catchers of the type in which a slub is detected by being deflected laterally of the normal yarn path by means of an inclined blade. Heretofore such devices have employed a slot having a Width slightly greater than the dimension which is generally accepted as the diameter of the yarn. For example 30s cotton yarn is considered to have a diameter of .007 inch, and the typical slot width for this yarn would be .008 inch. The considerations which led to use of such a slot width are as follows. Making the slot narrower tends to cause the device to catch yarn which though slightly larger than average is nevertheless completely acceptable yarn, and also causes the device to strip fibers from the yarn. Making the slot wider tends to make the device less reliable in detecting and removingsoft slubs. The removal of these softslubs would be better if the width of the slot was considerably less than the normal uncompressed diameter of the yarn and small ehough to materially compress the yarn, for instance 0 04 inch. However, this has been impracticable'because of the risk of catching the yarn itself and the stripping effect upon the yarn and resultant injury to the yarn and 'creation of fly.

v For 30s cotton, whose diameter is considered to be 0.007 inch, passage through a 0.004 inch slot would bring it to a fairly solid state while Within the slot. Norinally, the fibers of the yarn do not lie in'suchsolidstate dueto their crirnp and curl Compressive force'is necessary to bring a yarn into this solid condition, and the fibers exert counter force on'the blades between which theyarn is confined. Since the fibers are not of conii'ridr these conditions.

The present ihvention maybe regarded as providing a slub'detctingaction comparable to that of such an unduly narrow slot, but without the drawbacks which would make such slot impracticable, and particularly tinuou's length, stripping of the fibers would take place without confinement of the yarn such a'swould-caus'e accept able yarn to be caught, and cause fibers to be stripped from the yarn and fly to becreated.

The invention involves use of the observationthat' the normal yarn can run in its normal path, without risk'of being caught or stripped, even when the normal path is bounded by two inclined yarn-engaging elements or blades which are spaced considerably closer (measuring perpendicularly to the yarn path) than'the' diameter of the yarn, provided the place where the yarn meets the entrance edge of the second element or blade is spaced yarn last engages the surface 'of the first element or blade, i'.e., the yarnengaging portions are not'o'ppos'edand do not compress "the yarn between them.

The invention further involves use of the dis'covry that the yarn may be bounded by these relatively closely laterally spaced but non-opposed surfacesnot being'c'onfin-ed under pressure between them, and yet a softslh b be Idefiected more'strongly than by "aconventionals'lot havcizig; :onventional dimensions, i.e., 'a conventional slotof ice 2 slightly greater width than'the accepted diameter of the yarn. Yet with the non-confinement of the yarn at the normal yarn path the tendency to deflect slightly oversize yarn is reduced and stripping of these yarns is avoided.

It will be seen that with two yarn-engaging surfaces arranged in this closely spaced non-confining manner they tend to bend a slub twice, in one direction as it leaves the surface of the first yarn-engaging element, and then in the other direction around the entrance edge of the second yarn-engaging element.

The slub, like the remainder of the yarn, is under tension and accordingly resists this double bending and presses against both elements. These elements accordingly react on the slub. Thus the yarn tension induces a reaction on the slub notwithstanding that the slub is not squeezed between opposed surfaces at the time of this reaction.

Assuming that the yarn runs upwardly, the reaction of the entrance edge of the second yarn-engaging element or blade upon the bent slub is partly downward and will have a component perpendicular to the inclined direction of the blade, thereby resisting travel past the blade and promoting deflection of the slub up the. inclined edge of the blade, even though this reaction is exerted from only one side of the slub.

It might be thought that, if the tension could induce a somewhat downward reaction on the slub where it tends to bend around the entrance edge of the upper yarn-engaging'element, the tension would also induce a somewhat upward reaction on the slub Where it tends to bend in the opposite direction in leaving the first yarnengaging element. However, the action of the lower yarn-engaging element does not, in'fact, appear to nullify theeifect at the upper element.

It seems probable that the somewhat upward reaction of the first yarn-engaging element which would in theory result 'from the slubs resistance to bending at the first yarn-engaging element is wholly or partly overcome by the downwardly directed force of friction upon the slub at this element whereas the downward reaction oi. the second yarn-engaging'element'is augmented by another downwardly directedforce of friction at this second element;

7 It will be seen that a snubbing friction is applied to the slub by both the last-engaged surface of the first yarh engaging element and the entrance edge of the second yarn-engaging element.

The net of the reactions due to tension and friction appears to result in an effective component of force applied by the entrance edge of the second yarn-engaging element, perpendicular to its inclined direction, and hence causing a lateral deflection.

The lower inclined yarn-engaging element may be regarded as serving as a guide to cause a slub to approach the upper inclined yarn-engaging element in a direction such that a slub will bend around this upper element. The entrance edge of this upper element should be an abrupt, that is say, not rounded, edge so as to apply force most effectively to the slub.

The deflected slub may be trapped between opposed members and the yarn thereby caused to break.

The invention provides a number of advantages.

Although there should naturally be different settings for different ranges of yarn numbers, with the present invention the setting is not so critical as with previous device-s, and a given spacing will satisfactorily accommodate a greater'range of'yarn numbers than in the previous devices. The setting of a conventional slub catcher is best accomplished by providing elements which together will not strip the yarn. Now that confinement of the yarn in the normal running position is no longer a factor, the setting need no longer. have this close relation to the normal yarn diameter, and a given setting can satisfactorily take care of a larger range of yarns than before.

Since the action of the slub catcher does not depend on pressure confinement of the yarn between opposed surfaces, the action upon the yarn is more gentle, the production of fly is minimized and accumulation of fly such as takes place in a conventional slot is prevented.

Heretofore the tension in the yarn had a considerable effect upon the sensitivity of the slub catcher. Comparing the yarn to a bow string, more force is required to deflect a highly tensioned bow string than a bow string having a low tension. The new slub catcher has a feature of self-compensation for diflerences in this tension. Although greater tensions still require greater forces for a given deflection, the greater tension 110W causes the slub catcher to exert a greater reaction on the slub, thus providing greater deflecting force as required.

Other advantages and objects of the invention will be apparent from this specification and its accompanying drawings in which the invention is explained by way of example.

The example of the new slub catcher herein shown is relatively simple. It will be apparent to those skilled in the art how the present invention detects and deflects the slub, and how its principle may be incorporated along with additional features, additional blades, and provision for releasing a knot, as in my United States Patent No. 2,625,732, dated January 20, 1953, and my application for patent on a slub catcher (Case A) filed contemporaneously herewith.

In the accompanying drawings,

Fig. 1 is a view mainly in front elevation showing the front cover plate of a traveling spindle winding unit with parts removed;

Fig. 2 is a view mainly in vertical section on the line 22 of Fig. 1 which is also the normal yarn path;

Fig. 3 is a diagram in the nature of a left side elevation of the two blocks of the slub catcher, to greatly enlarged scale and showing both the normal running position of the yarn and a position to which the yarn is deflected when a slub is encountered;

Fig. 4 is a face view of the adjacent portions of the stationary and movable blocks of the slub catcher, taken on the line 9-9 of Fig. 3;

Fig. 5 is a face view of the blocks of the slub catcher from the same point of view as Fig. 4 but to a smaller scale;

Fig. 6 is a view like Fig. 5 except that the upper blade of the stationary block has been cut away to show the lower blade of the stationary block;

Fig. 7 is an end view of the movable and stationary blocks;

Fig. 8 is a view like Fig. 7 showing a modification of the stationary block;

Fig. 9 is a vertical section taken at right angles to Fig. 3 through the vertical path of the normally running yarn looking to the left, and for simplicity of illustration omitting the structure lying behind the plane of this section;

Fig. 10 is an elevation of the right side or operative face of the pivotally mounted block; and

Fig. 11 is a plan of the block of Fig. 10.

In the preferred form of slub catcher illustrated, the yarn Y runs as in Fig. 1 between a stationary block 10, which is cut away on its, left face, as subsequently described, to form an upper yarn-engaging element or blade and a lower snagging blade, and a pivotally mounted block 11, which is cut away on its right face to receive the yarn. Fig. 1 exaggerates this cutting away of the block 11.

As shown in Fig. 2, the front cover plate 15 of a winding unit carries a base block 16. The stationary block 10 is secured in an inclined position to a corresponidng inclined surface of the base block 16. The pivotally mounted block 11, Fig. 1, is rotatable by a spindle 18, having a pivot portion which passes through the movable block and pivots in the base block as indicated at 19 in Fig. 2.

The spindle 18 is yieldingly urged against the movable block 11 by the pressure of a spring 20, under the influence of a set screw 21, which pressure, however, can be released to permit the movable block 11 and spindle to be disassembled. The spindle 18 and block 11 can be rotated by an arm 18a manually or mechanically to tilt the movable block away from the observer in Fig. 1 and downwardly in Fig. 2 to open the slub catcher and expose the normally opposed faces of the two blocks for cleaning as by an air blast. This tilting of the movable block is similar in principle to the tilting of the movable member of the slub catcher of United States Patent No. 2,732,610 of Winthrop L. Perry.

The usual yarn guides 23 and 24, above and below the slub catcher, guide the yarn in a straight vertical path in its upward travel from a supply to the winding package and a usual tension device 25 applies the desired tension.

The deflecting action of the slub catcher upon an enlargement in the yarn is to the left in Fig. 2 and away from the observer in Fig. 1. A guide bracket 27 engages the yarn below the slub catcher and is adjustable vertically to vary the length of yarn that can be deflected, that is, the length of the bow-string which is formed when the yarn is deflected, thus to vary the sensitivity of the slub catcher.

The pivotally mounted block 11 best shown in Figs. 10 and 11 is cut away by grinding on its face which opposes the block 10 to receive the yarn, the extent of this cutting away, dimension A, being exaggerated in Fig. 11. An inclined surface portion B of the block 11 defines a tapered snagging slit in conjunction with a blade surface of the block 10.

It may be mentioned that, for converting the device to handle various yarn numbers, removable blocks 11 are provided in a range of dimensions A, the setting of the slub catcher being determined by this dimension A of the removable block, and the dimensions and form of the companion stationary block 10 being constant.

The stationary block 10 is essentially rectangular with various cut away surfaces.

A V-shaped slot divides the operative left face of the block 10 into an upper blade 40 and a lower snagging blade 41, the effective faces of which blades preferably lie in the same vertical plane which is in prolongation of the plane of the rear portion of the right face of block 11.

As shown in Fig. 6 the snagging blade 41 is chamfered at its outer end so that in the normal running position of the yarn of Fig. 2 this blade is well out of contact with the yarn. The chamfered edge of blade 41 will however serve to guide yarn into the slit between this blade and the movable block 11.

Although the upper surfaces of the stationary and movable blocks are parallel, being inclined from the yarn path at the same approximately 40 angle, the upper surface of the movable block 11 is sufliciently lower than the stationary blade 40 to leave a gap G (Fig. 3) of approximately inch between these elements.

In the normal running position the yarn engages only the block 11 and blade 40, and because of the gap G will leave the first of these yarn-engaging elements, block 11, before engaging the second yarn-engaging element, blade 40. The setting between the blocks at the normal yarn path, measured perpendicular to the yarn path and indicated at S in Fig. 9 is such that if the blade 40 were opposite to the block 11 the yarn would have to be considerably compressed, to a fairly solid condition, in order to pass between these. As indicated above, for 30's cotton which is considered to have a diameter of 0.007 mch, the setting of the previously employed slub catcher of the inclined blade type would be 0.008 inch, but for this same yarn the setting S of the present device would be 0.004 inch. However, there are no opposing surfaces that actually compress the yarn in the manner of a conventional slot of this reduced width. The-kinky, curly fibers of the yarn are free to extend out as in unconfined yarn except where fibers wipe against the surface of block '11 or the surface of blade 40. This wiping of the fibers against these surfaces which are non-opposed does not exert any appreciable stripping action upon somewhat oversize yarn.

Because the lateral setting S, though materially smaller than the setting of the conventional slot for the same yarn, still represents a considerable fraction of the normal yarn diameter, and because those fibers that Wipe past the block 11 and blade 40 can flatten into the body of the yarn as they wipe past these surfaces, there is no appreciable bending of the normal yarn as a whole from a straight path as it encounters the blade 40. Nevertheless the relation of the block 11 and blade 40 is such that the tensioned yarn will bear against the blade 40, but with little resulting reaction upon the yarn so long as an enlargement of substantial bulk is not encountered.

When a slub reaches the entrance edge 40a of the blade 40, then, because the yarn already bears against this blade, the blade immediately tends to bend the slub bodily. The slub resists such bending and reacts strong ly on the blade, and the result is a strong downward component of "force applied to the slub perpendicular to the blade and tending to deflect the yarn along the blades, to the left in Fig. 3.

Moreover, theslub is immediately subjected .to snubbing frictional action which contributes to the deflecting action which urges the slub up the inclined blades.

As indicated above, the net of the bending reactions and frictional reactions appears to include a strong downward component perpendicular to the inclined blade 40. This reaction is indicated by the force line R in Fig. 3 and results in deflection of the slub to the left of the normal yarn path and up the inclined blades.

Since the leading edge 11a of block 11 remains parallel to the entrance edge 40a of blade 40 as these two edges progress upwardly and to the left in Fig. 3, the deflecting force continues to be applied to the slub as it travels up these edges.

A relatively slight deflection of the slub causes it to encounter the operative face of the lower blade 41. This blade operating in conjunction with the opposed block 11 provides an additional deflecting action. The slub is thus carried into the tapered snagging slit which tapers to zero width by reason of the tapered surface of block 11 in its region B as above described, this effectively snagging any part of the yarn that has been deflected into this region of the slit. A typical snagging position of the deflected yarn is shown at S in Fig. 3.

A properly tied knot or short enlargement such as a nib will usually escape through the gap G before there is enough deflection to bring the yarn into range of the operative face of lower blade 41, whereupon the yarn will return to its normal running position wtihout being snagged.

It is not considered essential that the face of the lower blade 41 lie in the same plane as that of the upper blade 40, and the lower blade can contribute somewhat to the deflecting action if before the tapered snagging zone is reached the space between blade 41 and the block 11 is about the same as the conventional setting of slant type slub catchers, for instance as much as 0.008 inch for 30s cotton.

Although for manufacturing reasons it is simpler to have the face on the lower blade parallel to, although not necessarily in the same plane as, the face of the upper blade, this is not essential, and the face of the lower sitely disposed surface.

6 blade may gradually converge toward the face of :block "11 so as to exert a progressively increasing deflecting action, supplementing that ofthe upper blade, as the bow string of yarn becomes more widely deflected and requires a greater deflecting force.

"Ishas been customary to make the blades of slant type slub catchers narrow so as to reduce the lateral friction as a deflected slub moves up the blades. This factor of narrowness of blades becomes of little importance with the present invention because the yarn is not squeezed between blade 40 and block -11 until it has almost reached the snagging position. Blade 40 can accordingly be considerably widened as shown for example in Fig. 8 without substantially increasing this lateral friction, and such widening of this blade should prove helpful in decreasing wear at the normal running position of the yarn.

I am aware that British patent specification No. 747,836 shows slub catchers in which after detection of a slub the yarn becomes bent around an edge face of a plate without being pressed against this face by an oppo- In these prior slub catchers the bending is for the purpose of breaking the yarn. These prior slub catchers differ in principle from thepresent slub catcher in that .they do not cause the yarn in the normal yarn path to bear laterally, but without .pressure confinement, against a surface arranged to detect a slub at that poin, but detect the slub by a conventional slot and use this conventional 'slot to deliver the yarn to a path in which it will become, in effect, clamped and will break.

I claim:

1. A slub catcher comprising means defining a normal yarn path, elements on opposite sides of said path, said elements having non-opposed yarn-engaging surfaces engageable with the yarn at said normal yarn path at said opposite sides at successive places, said surfaces being so related to each other and the normal yarn path that the first surface urges the yarn to bear against the second surface due to the yarn tension without bending the yarn appreciably out of straight line travel at the entrance to the second surface, the last engaged portion of the first surface and the first engaged portion of the second surface extending on an incline away from the normal yarn path and forming a passage along which a slub is deflected from the normal yarn path as the slub encounters said second surface, the slub catcher including a snagging slit outside of the normal yarn path for receiving the yarn when a slub is thus deflected.

2. A slub catcher comprising means defining a normal yarn path, elements on opposite sides of said path, said elements having non-opposed yarn-engaging surfaces engageable with the yarn in said normal yarn path at said opposite sides thereof, said surfaces being spaced at the normal yarn path with a spacing transversely of the yarn path corresponding to a material compression of the yarn if said surfaces were opposed to each other, the last engaged portion of the first surface and the first engaged portion of the second surface at the normal yarn path however being spaced longitudinally of the yarn path and the yarn not being subjected to such compression, said last engaged portion and said first engaged portion of the respective surfaces extending on an incline away from the normal yarn path and forming a passage along which a slub is deflected from the normal yarn path as the slub encounters said second surface, the slub catcher including a snagging slit outside of the normal yarn path for receiving the yarn when a slub is thus deflected.

3. A slub catcher comprising means defining a normal yarn path, elements on opposite sides of said path, said elements having non-opposed yarn-engaging surfaces engageable with the yarn at said normal yarn path at said opposite sides, the last engaged portion of the first said surface and the first engaged portion of the second said surface at the normal yarn path being spaced longitudinally of the yarn path, the yarn being free from pressure confinement between said two surfaces, there being a lateral spacing between said surfaces at the normal yarn path and transverse thereto such that the normal yarn is not appreciably bent out of straight line travel at the entrance to the second surface but the first surfaces causes the yarnto bear against the second surface, said last engaged portion and said first engaged portion of the respective surfaces extending on an incline away from the normal yarn path and forming a passage along which a. slub is deflected from the normal yarn path as the slub encounters said second surface, the slub catcher including a snagging slit outside of the normal yarn path for receiving the yarn when a slub is thus deflected.

4. A slub catcher comprising means defining a normal yarn path, elements on opposite sides of said path, said elements having non-opposed yarn-engaging surfaces engageable with the yarn atsaid normal yarn path at said opposite sides, the last engaged portion of the first said surface and the first engaged portion of the second said surface at the normal yarn path being spaced longitudinally of the yarn path, there being a lateral spacing between said surfaces at the normal yarn path and transverse thereto such that the normal yarn is not appreciably bent out of straight line travel at the entrance to the second surface but the first surface causes the yarn to bear against the second surface, said last engaged portion and said first engaged portion of the respective surfaces extending on an incline away from the normal yarn path and forming a passage along which a slub is deflected from the normal yarn path as the slub encounters said second surface, the slub catcher including a snagging slit outside of the normal yarn path for receiving the yarn when a slub is thus deflected, there being at the normal yarn path no opposing surfaces sufficiently close to either of said yarn-engaging surfaces to press substantially oversize yarn against said yarn-engaging surfaces, such oversize yarn bearing against said yarn-engaging surfaces in succession solely by reason of the tension in the running yarn and'the positioning of said 'yarn-engagingsurfaces relative to the yarn path, so that oversize yarn is not subjected to stripping.

5. A slub catcher comprising first and second yamengaging members between which the yarn runs, the second of said members having two blades, the entrance edge of the upper of said blades being substantially parallel to but spaced above the last-engaged surface of the first yarn-engaging member, the lower of said blades being opposed to said first member and being cut away to avoid contact with the yarn at the normal undeflected running position of the yarn, said entrance edge of the upper blade and said last-engaged surface of the first yarn-engaging member being so located in the region of normal substantially straight line travel of the yarn that a slub in said region is urged to bend around said entrance edge of the upper blade, said edge and said surface being inclined to the normal direction of travel of the yarn so that the slub is laterally displaced along said edge and surface out of the region of normal travel of the yarn, the lower blade and first member converging to trap the displaced slub.

References Cited in the tile of this patent UNITED STATES. PATENTS 2,746,120 Moos May 22, 1956 

